We propose to continue our current research on the assessment of environmentally occurring pesticide terminal residues on mammalian learning and behavior. Particular emphasis will be placed on the effects of very low dietary dosages incurred over long periods of time (two to three generations). Current compounds under study are dieldrin, chlordimeform and toxaphene. The last compound is being used not only in the technical grade, but the second most toxic fraction (toxicant B) of the complex. Toxicant B will be incorporated in diets at a level of 2 ppb. The other two compounds will be tested in diets at ten times WHO suggested usage levels. In addition to adequate nutritive diets, rats will be placed on low protein diets so that the possible effects of deitary stress, coupled with toxicants, can be evaluated. Upon completion of the behavioral testing, post-mortem investigations will be conducted.